Sold OMG gas guzzler Yank tank: Bid accepted, car delivered!

[eddyramrod]

Well yesterday was fun*...  I had a drive round Barrow talking to people at several garages that I haven't visited before.  Oh yeah, we can't do anything with that, see this fella... and so on.  Eventually I turned up at this one garage: yeah, should be able to look at that, can you bring it round today?  So I did.  His lovely new Launch scanner had an adaptor that fitted the terminal on the car, good start.  Going through the menus, Ford (USA and Canada), good, click, scroll.... 93 Sable 3.0, even better.  It got as far as scanning the system, then decided there was a "communication error" and wouldn't talk to the car any more.  Driving home it felt great, the display was working, the trans was shifting almost normally, but it had been sitting running for some time while the scanner was attached, so it had plenty of time to warm up.  Took it to work this morning and back to square one.

[vulgalour]

Wish I had some advice or a suitable car to offer you with this one, it really does sound like a very odd and niggly electrical fault and it's a shame you can't just visit a local breaker and try a different console to see if that eliminates the fault.

[eddyramrod]

I agree!  I see now where I made my big mistake.  I should have moved to Tennessee instead of Cyprus.  Wouldn't be a problem then!

[rainagain]

It makes me sad thinking you want to sell this car due to the speedo fault.

 

You are actually in a really good position with this fault as you know exactly when it happens which makes finding the cause a 1000% easier than a random fault.

 

If we try and break the speedo system down into chunks we get the following main components:

 

1.       Speed sensor – could be from the gearbox or via one of the ABS sensors

2.       Cable from this to the LCD display panel or ECU

3.       If speed sensor terminates at ECU cable from ECU to LCD display panel

4.       LCD display panel

 

We can test some of the above without too much specialised kit. Ideally you want to borrow a portable scope and have a look at the output from the speedo sensor. A quick google found me this about using a scope to diagnose a faulty speed sensor and show a typical square wave output:

 

http://www.picoauto.com/tutorials/the-versatile-scope2.html

 

If you can’t get the lend of scope you should be able to use something like this although it doesn’t state the min of max frequencies it can measure, although as most car electronics is not exactly super fast cutting edge it should be ok:

 

http://www.ebay.co.uk/itm/Digital-LCD-Multimeter-DMM-Frequency-Measurement-Auto-range-Max-Data-Holding-UK-/191100534241?pt=LH_DefaultDomain_3&hash=item2c7e7abde1

 

So armed with something to measure frequency you could start our diagnostics as follows:

 

1.       We know it doesn’t work when it’s cold so find the sensor and jack the car up remove the wheels. Using a sharp probe pierce the signal output from the speed sensor, if you can’t get hold of a wiring diagram check each of the wires with the meter set to voltage, if it’s two wires one should be a constant voltage (signal output) when the ignition on and the other will be ground. If it has three wires like the one shown in the hyper link, one will be ground, one will be the power and the remaining one will be the output. You can check it’s ground by setting the meter to ohms and checking for a low resistance (less than 5 ohms) between the ground wire and a good clean chassis earth. If none of the cables have a voltage on them, then the fault might be with the cable or the supply to the cable.

2.       Once you have identified the signal output start the engine up and look at the output on the scope/meter if there is no output then either woohoo you’ve found the fault of you’ve got the wrong wire

3.       To confirm this wait until the car is warmed up and the fault is gone and the repeat this test, if there’s still no signal you are looking at the wrong wire so check the other ones, once you’ve found the correct one mark it and then repeat the test the following day when the car is cold.

4.       If you now have a signal on your wire it is likely the sensor is faulty.

5.       If there was a signal there the whole time when cold we need to move onto component two the cable. Trace the output cable back to either the ECU or LCD display and again piece the wire and check for a signal, if there was a signal at the sensor end of the cable but not the other end then we have a break in the cable.

6.       If the cable and sensor are all fine then the fault probably lies with the display or the ECU output to the display, as mentioned before most likely a dry joint or bad connection. I would recommend taking all the connectors apart and cleaning them with a good quality contact cleaner spray and this will break down any oxidation on them.

 

Make sure the ABS light on your car self resets as with quite a few cars running the front wheels off the ground tends to bring on an ABS error as the front wheel speed is massively different from the rear stationary wheels. Some cars need to have the light turned off via the diag port, most self reset.

 

From what you’ve said I think it has a speed sensor built into the gearbox, also you didn’t mention the ABS light coming on, if the speed sensor was from the ABS sensor and this was faulty it would put the ABS light on. You said you replaced two sensors in the gearbox, what were they? If you have replaced the speed sensor in the gearbox already, my money is on either the cable that feeds it, or it’s connection at the other end. I hope above helps and if you try any of it please let me know how you get on.

[purplebargeken]

I'll give you 100 quid for it. Plus a KFC meal 'cos it is American.

[hairnet]

eddy - marry the scottish man wit the advice

[Taff]

I'll give you 100 quid for it. Plus a KFC meal 'cos it is American.

 

I'll give you $100 and a Happy Meal...

[eddyramrod]

Rainagain: thank you.  Those are the most sensible words anyone has typed since this issue first occurred.  I may well print out your posting and take it down to Martin!  (Far better he does the actual work, my back still isn't right)

 

Ken and Taff: at last, bids!  Now I just need some slightly more realistic and I could well be an ex-Mercury owner.

[panhard65]

I know how "good" American ecu's are so that is where I would start. There is a Polish autoelectrician round the corner from me who would take it apart and fix it. Not that it would be much use as I am in Somerset. You could try BBA Reman to see if they can have a look. I have only had to replace 2 ecu's in the last 10 years or so. 1 was a Laguna so doesn't really count as they were rubbish out of the factory. The other was a Chrysler Le baron which was just rubbish but rock auto supplied a new replacement for not too silly money.

[panhard65]

Oh nearly forgot £150 and a bottle of scrumpy providing it stands a slight chance of driving home to Somerset

[eddyramrod]

Bottle of scrumpy?  Clearly my alcohol policy isn't as well-known as I thought... 

 

BTW, who or what is BBA Reman?

[panhard65]

 http://www.bba-reman.com/uk/index.aspx

ECU repairs. You may even have someone local who can pull it apart and fix the dry joints or corroded circuit board that it will most likely have. May be worth trying your local Maplins and ask them if they know anyone who is good at repairing ecu's. I know my Polish chap is always in there buying resistors etc.

[purplebargeken]

The scrumpy wasn't for you to drink

 

Think how much you'd enjoy that KFC.

[eddyramrod]

Thank you, I've got their site up now.  I can't see the actual ECU being the problem, simply because the engine still works, and perfectly too.  It isn't going into any kind of rev-limited mode, for example; still feels like it's firing on all 6 and there's plenty of power when I want it.  Point taken about dodgy joints though, that remains a possibility.

[panhard65]

I am no expert on Yanks but it might have a seperate ECU for the gearbox. As you say it messes about and won't change gear correctly when the fault is present. That would make me think the speed sensor feeds the ecu then the dash display. Sometimes this will all be in the one ecu for engine and gearbox. I have got a Launch diagnostic machine as well and they can get a bit tempermental and not always connect, a bit of a pain if you are paying someone to do it but it will connect eventually.

[eddyramrod]

Paying someone, yeah, that's one of the big stumbling blocks.  But, if you don't have the skills/information/equipment/safe place to work then that's what you have to do.  Well it's what I have to do anyway.  Not having a manual is a pain!  I thought the US-based club forum would be helpful but apparently not.

[eddyramrod]

I've just found a set of factory manuals on ebay and ordered them.  Far side of 35 notes because shipping from America but might be a good investment.  And they will stay with the car when it sells (special enhanced offer!).

[eddyramrod]

Has it really been a month?  Dear me.

 

Well, the tax ran out, so I sorned it and now it's parked at the back of Dave862's driveway while we fiddle about with it at weekends.  The manuals came.  We tested everything we could get at with his multimeter and couldn't find anything amiss (which might not mean anything).  I've removed the instrument pod and a control circuit from under the dash, and taken them to a local sparky to test.  I got them back today, clean bill of health as far as he can tell.  So I reckon they will be going back in this weekend.

 

I could not be more pissed off with it.  I guarantee it'll be a something-and-nothing fix, but I don't have the skills, nor, it seems, does anyone around me.  Someone please take it away.

[eddyramrod]

£400 would buy it.  That just about covers what I spent on the suspension.  The car, and the new stuff it's had since, are effectively free.

[Bear]

*fingers in ears*

*covers eyes*

Can't see it. Can't hear about it. It doesn't exist. I'm not going to be in America soon and able to look for spares. Nope.

[320touring]

£400 would buy it. That just about covers what I spent on the suspension. The car, and the new stuff it's had since, are effectively free.

So it goes into limp mode and cannae be driven very far?

[eddyramrod]

It probably could be, but I wouldn't be prepared to take that chance.  It's done work-and-back many times since this all started, but I haven't taken it any further in case it damages the gearbox. 

[320touring]

It probably could be, but I wouldn't be prepared to take that chance. It's done work-and-back many times since this all started, but I haven't taken it any further in case it damages the gearbox.

Ach, bit too far to glasgow then..

 

Glwts!

[eddyramrod]

Thank you.

 

Of course, it's only the size of a Jag, so shouldn't be that hard to piggyback up there?  Or anywhere else?

[eddyramrod]

Nyphur, I agree with you, but I'm afraid all those bases are covered.  I have reached the end of my skillset, and it seems impossible locally to find someone who I could pay to apply theirs.  Always assuming I could pay at all!  I now firmly believe the best place for it is the oval.  I certainly don't want to keep it myself.

[eddyramrod]

The wipers and radio are fine.  The gearbox doesn't seem to do anything "more normal" once warm, and believe me, I've given it some good warming-up in the hope of curing it.

The speedo displays a zero, and the odo displays the last reading it stopped at, until they decide they're warm enough to join in.  Everything else displays as normal.  This is what's puzzling.  If the whole display had shut down I could blame a fuse, and go looking for them, but for just two (related) items to half-function....

I'll be putting it back together tomorrow, weather permitting, and it can go then.

[eddyramrod]

VSS is new, no problems with the fuses..... it is, as Toyah famously sang, a Mystery.  Oh it's a mystery, I'm still searching for a clue.  Is it a mystery to you too?

[Bear]

Really wish I was closer and not fucking off to the states in a few days. Well, not quite wish that bit, but you know I've got room and could spend some time attacking this. Bah.

[eddyramrod]

The thought was there and I appreciate it on that level.  You go and have fun with Marvin.

[Formula Autos]

_{Eddy, how about trying the experts at Car Mechanics magazine? They run a section at the back of the mag where they diagnose frustrating problems like this. Here's their e-mail address:}

 

_{[email protected]}

 

_{Hopefully they can help and, if they do, you'll have appeared in another motoring publication.}